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fix: cross-chunk CJS wrapper shadowed by author-local binding#9648

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06-04-fix_9630
Jun 4, 2026
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fix: cross-chunk CJS wrapper shadowed by author-local binding#9648
graphite-app[bot] merged 1 commit into
mainfrom
06-04-fix_9630

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@IWANABETHATGUY

@IWANABETHATGUY IWANABETHATGUY commented Jun 3, 2026

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Fixes #9630.

Problem

When code-splitting hoists a CommonJS require_* wrapper into a different chunk than the module that require()s it, an author's local binding of the same name shadowed the imported wrapper. This happens in real code — es-toolkit's compiled output literally writes var require_isArrayLike = require("./isArrayLike.cjs"), whose local matches the wrapper name rolldown derives from the filename.

The lazy chunk then emitted the self-referential:

import { n as __commonJSMin, t as require_isArrayLike } from "./isArrayLike.js";
var require_last = __commonJSMin(((exports) => {
  var require_isArrayLike = require_isArrayLike(); // local shadows the import
  ...

The hoisted var resolves to itself (undefined), throwing TypeError: require_isArrayLike is not a function at runtime. (A subsequent DCE pass also drops the now-"unused" import, so the import disappears entirely — but the crash is the same either way.)

Root cause

deconflict_chunk_symbols already guards against an author-local inside a CJS __commonJS((exports, module) => { ... }) closure shadowing a name captured at the chunk's root scope (issues #9055 / #9375). It does this via chunk_scope_captured_names — but that set was only seeded from wrappers of modules in the current chunk.

A wrapper hoisted into another chunk is imported here as a real root-scope binding (import { ... as require_foo } from "./other.js") and is equally captured by every CJS closure in this chunk, yet it was invisible to that loop. So the colliding author-local was not deconflicted.

Fix

Seed chunk_scope_captured_names from cross-chunk CJS wrapper imports too (chunk.imports_from_other_chunks), the symmetric counterpart to the existing in-chunk wrapper loop. The colliding local is now renamed, matching the same-chunk output:

import { n as __commonJSMin, t as require_isArrayLike$1 } from "./isArrayLike.js";
var require_last = __commonJSMin(((exports) => {
  var require_isArrayLike = require_isArrayLike$1();
  ...

Test

Adds tests/rolldown/issues/9630, a minimal reproduction (eager import of the leaf + dynamic import of the requirer to force the cross-chunk split). The fixture executes the bundled output, so it fails on the runtime TypeError without the fix and passes with it.

Verified regression-free: full rolldown fixture, esbuild, and rollup snapshot suites pass with zero existing-snapshot changes.

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@IWANABETHATGUY IWANABETHATGUY changed the title fix: 9630 fix: cross-chunk CJS wrapper shadowed by author-local binding Jun 3, 2026
@IWANABETHATGUY IWANABETHATGUY marked this pull request as ready for review June 4, 2026 01:58
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Merging this PR will not alter performance

✅ 4 untouched benchmarks
⏩ 10 skipped benchmarks1


Comparing 06-04-fix_9630 (c581aac) with main (696cad1)2

Open in CodSpeed

Footnotes

  1. 10 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports.

  2. No successful run was found on main (8739a75) during the generation of this report, so 696cad1 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report.

IWANABETHATGUY commented Jun 4, 2026

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Merge activity

  • Jun 4, 2:07 AM UTC: The merge label 'graphite: merge-when-ready' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
  • Jun 4, 2:07 AM UTC: IWANABETHATGUY added this pull request to the Graphite merge queue.
  • Jun 4, 2:17 AM UTC: Merged by the Graphite merge queue.

graphite-app Bot pushed a commit that referenced this pull request Jun 4, 2026
Fixes #9630.

## Problem

When code-splitting hoists a CommonJS `require_*` wrapper into a different chunk than the module that `require()`s it, an author's local binding of the same name shadowed the imported wrapper. This happens in real code — es-toolkit's compiled output literally writes `var require_isArrayLike = require("./isArrayLike.cjs")`, whose local matches the wrapper name rolldown derives from the filename.

The lazy chunk then emitted the self-referential:

```js
import { n as __commonJSMin, t as require_isArrayLike } from "./isArrayLike.js";
var require_last = __commonJSMin(((exports) => {
  var require_isArrayLike = require_isArrayLike(); // local shadows the import
  ...
```

The hoisted `var` resolves to itself (`undefined`), throwing `TypeError: require_isArrayLike is not a function` at runtime. (A subsequent DCE pass also drops the now-"unused" import, so the import disappears entirely — but the crash is the same either way.)

## Root cause

`deconflict_chunk_symbols` already guards against an author-local inside a CJS `__commonJS((exports, module) => { ... })` closure shadowing a name captured at the chunk's root scope (issues #9055 / #9375). It does this via `chunk_scope_captured_names` — but that set was only seeded from wrappers of modules **in the current chunk**.

A wrapper hoisted into another chunk is imported here as a real root-scope binding (`import { ... as require_foo } from "./other.js"`) and is *equally* captured by every CJS closure in this chunk, yet it was invisible to that loop. So the colliding author-local was not deconflicted.

## Fix

Seed `chunk_scope_captured_names` from cross-chunk CJS wrapper imports too (`chunk.imports_from_other_chunks`), the symmetric counterpart to the existing in-chunk wrapper loop. The colliding local is now renamed, matching the same-chunk output:

```js
import { n as __commonJSMin, t as require_isArrayLike$1 } from "./isArrayLike.js";
var require_last = __commonJSMin(((exports) => {
  var require_isArrayLike = require_isArrayLike$1();
  ...
```

## Test

Adds `tests/rolldown/issues/9630`, a minimal reproduction (eager import of the leaf + dynamic import of the requirer to force the cross-chunk split). The fixture executes the bundled output, so it fails on the runtime `TypeError` without the fix and passes with it.

Verified regression-free: full rolldown fixture, esbuild, and rollup snapshot suites pass with zero existing-snapshot changes.
Fixes #9630.

## Problem

When code-splitting hoists a CommonJS `require_*` wrapper into a different chunk than the module that `require()`s it, an author's local binding of the same name shadowed the imported wrapper. This happens in real code — es-toolkit's compiled output literally writes `var require_isArrayLike = require("./isArrayLike.cjs")`, whose local matches the wrapper name rolldown derives from the filename.

The lazy chunk then emitted the self-referential:

```js
import { n as __commonJSMin, t as require_isArrayLike } from "./isArrayLike.js";
var require_last = __commonJSMin(((exports) => {
  var require_isArrayLike = require_isArrayLike(); // local shadows the import
  ...
```

The hoisted `var` resolves to itself (`undefined`), throwing `TypeError: require_isArrayLike is not a function` at runtime. (A subsequent DCE pass also drops the now-"unused" import, so the import disappears entirely — but the crash is the same either way.)

## Root cause

`deconflict_chunk_symbols` already guards against an author-local inside a CJS `__commonJS((exports, module) => { ... })` closure shadowing a name captured at the chunk's root scope (issues #9055 / #9375). It does this via `chunk_scope_captured_names` — but that set was only seeded from wrappers of modules **in the current chunk**.

A wrapper hoisted into another chunk is imported here as a real root-scope binding (`import { ... as require_foo } from "./other.js"`) and is *equally* captured by every CJS closure in this chunk, yet it was invisible to that loop. So the colliding author-local was not deconflicted.

## Fix

Seed `chunk_scope_captured_names` from cross-chunk CJS wrapper imports too (`chunk.imports_from_other_chunks`), the symmetric counterpart to the existing in-chunk wrapper loop. The colliding local is now renamed, matching the same-chunk output:

```js
import { n as __commonJSMin, t as require_isArrayLike$1 } from "./isArrayLike.js";
var require_last = __commonJSMin(((exports) => {
  var require_isArrayLike = require_isArrayLike$1();
  ...
```

## Test

Adds `tests/rolldown/issues/9630`, a minimal reproduction (eager import of the leaf + dynamic import of the requirer to force the cross-chunk split). The fixture executes the bundled output, so it fails on the runtime `TypeError` without the fix and passes with it.

Verified regression-free: full rolldown fixture, esbuild, and rollup snapshot suites pass with zero existing-snapshot changes.
@graphite-app graphite-app Bot merged commit 645ed62 into main Jun 4, 2026
34 checks passed
@graphite-app graphite-app Bot deleted the 06-04-fix_9630 branch June 4, 2026 02:17
@shulaoda shulaoda mentioned this pull request Jun 11, 2026
@rolldown-guard rolldown-guard Bot mentioned this pull request Jun 11, 2026
shulaoda pushed a commit that referenced this pull request Jun 11, 2026
## [1.1.1] - 2026-06-11

### 🚀 Features

- ecmascript_utils: introduce AstFactory for AST construction (#9682) by @hyf0
- drop no-op init calls for empty wrapped-ESM modules (#9678) by @IWANABETHATGUY

### 🐛 Bug Fixes

- resolver: honor package.json#type for .jsx/.tsx extensions (#9690) (#9699) by @IWANABETHATGUY
- hmr: report the full-reload reason for the invalidate-loop case (#9708) by @hyf0
- explicit `moduleSideEffects` from a hook must take priority over the `package.json#sideEffects` (#9688) by @sapphi-red
- keep the `rolldown-runtime` name for the standalone runtime chunk (#9685) by @shulaoda
- lazy-barrel: request all exports for entry barrels on first encounter (#9672) by @shulaoda
- finalizer: skip init_*() for tree-shaken wrapped ESM owners (#9669) by @IWANABETHATGUY
- order `chunk.imports` by execution order (#9654) by @chuganzy
- vite-resolve: preserve slash separators for Sass partial exports (#9546) by @cjc0013
- cross-chunk CJS wrapper shadowed by author-local binding (#9648) by @IWANABETHATGUY

### 🚜 Refactor

- precompute wrapped-ESM init metadata in generate stage (#9712) by @IWANABETHATGUY
- ecmascript_utils: fold construction ext traits onto AstFactory and delete AstSnippet (#9702) by @hyf0
- finalizer: finish ScopeHoistingFinalizer migration to AstFactory (#9701) by @hyf0
- finalizer: migrate module_finalizers/mod.rs to AstFactory (#9700) by @hyf0
- hmr: migrate hmr finalizer to AstFactory (#9695) by @hyf0
- plugin: migrate vite_build_import_analysis to AstFactory (#9693) by @hyf0
- scanner: migrate tweak_ast_for_scanning to AstFactory (#9683) by @hyf0
- always split runtime module first (#9419) by @IWANABETHATGUY

### 📚 Documentation

- tsconfig: correct auto-discovery resolution to match TypeScript (#9714) by @shulaoda
- design: plan to unify all internal AST construction (#9673) by @hyf0
- tsconfig: align reference resolution docs with TypeScript behavior (#9641) by @shulaoda

### ⚡ Performance

- avoid per-module join Strings in scope-hoisting concatenation (#9645) by @Boshen
- avoid intermediate Strings in the ESM export clause (#9644) by @Boshen
- reuse a scratch buffer for facade namespace names in the scanner (#9642) by @Boshen
- reuse the import-matching tracker stack across named imports (#9643) by @Boshen
- avoid cloning the per-chunk export-items map in render_chunk_exports (#9639) by @Boshen
- avoid CompactStr allocation in sorted-exports membership check (#9640) by @Boshen

### 🧪 Testing

- add more `moduleSideEffects` precedence tests (#9689) by @sapphi-red
- 9651: drop shimMissingExports from regression fixture (#9674) by @IWANABETHATGUY

### ⚙️ Miscellaneous Tasks

- update react repo links (#9711) by @iiio2
- remove outdated pnpm configurations (#9666) by @btea
- deps: update github actions to v2.81.5 (#9665) by @renovate[bot]
- testing: migrate test harness off deprecated inlineDynamicImports (#9710) by @IWANABETHATGUY
- hmr: delete commented-out dead code left from old register-module codegen (#9707) by @hyf0
- deps: update napi-rs toolchain (#9706) by @shulaoda
- deps: update rollup submodule for tests to v4.61.1 (#9676) by @rolldown-guard[bot]
- deps: update test262 submodule for tests (#9677) by @rolldown-guard[bot]
- deps: update oxc to 0.135.0 (#9670) by @Boshen
- pass ALGOLIA_APP_ID and ALGOLIA_API_KEY to void deploy (#9667) by @Boshen
- deps: update github actions (#9662) by @renovate[bot]
- deps: update rust crates (#9663) by @renovate[bot]
- deps: update rolldown-plugin-dts to v0.25.2 (#9661) by @renovate[bot]
- deps: update typos to v1.47.2 (#9660) by @renovate[bot]
- deps: update docs dependencies (#9657) by @bddjr
- deps: update typos to v1.47.1 (#9655) by @renovate[bot]
- deploy website in its own workflow, only on docs output change (#9650) by @Boshen
- publish to pkg.pr.new add pm and `commentWithDev` option (#9638) by @btea

### ❤️ New Contributors

* @chuganzy made their first contribution in [#9654](#9654)
* @cjc0013 made their first contribution in [#9546](#9546)
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Automatic code splitting: circular CJS chunk → uninitialized binding ('n is not a function') (es-toolkit via Recharts, Vite 8)

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